KANE etchant (stock solution) is a chemical solution mainly used in metallography. It consists of hydrochloric acid, distilled water and copper dichloride. Hydrochloric acid (HCl) is a strong acid that acts as an etchant, while copper dichloride (CuCl2) acts as an oxidizing agent. In metallography, the etchant is used to examine chromium-nickel steels. It enables visualization of martensite, a hard and brittle form of steel that results from a certain type of heat treatment. The chemical properties of the solution allow effective and precise etching, resulting in detailed and informative microscopic images. The application of etchant according to KANE (stock solution) leads to reliable and reproducible results in metallography.